/*-
 * Copyright (c) 2008 Christos Zoulas
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

#include "file.h"

#ifndef lint
FILE_RCSID("@(#)$File: cdf_time.c,v 1.12 2012/05/15 17:14:36 christos Exp $")
#endif

#include <time.h>
#ifdef TEST
#include <err.h>
#endif
#include <string.h>

#include "cdf.h"

#define isleap(y) ((((y) % 4) == 0) && \
    ((((y) % 100) != 0) || (((y) % 400) == 0)))

static const int mdays[] = {
    31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31
};

/*
 * Return the number of days between jan 01 1601 and jan 01 of year.
 */
static int
cdf_getdays(int year)
{
  int days = 0;
  int y;

  for (y = CDF_BASE_YEAR; y < year; y++)
    days += isleap(y) + 365;

  return days;
}

/*
 * Return the day within the month
 */
static int
cdf_getday(int year, int days)
{
  size_t m;

  for (m = 0; m < sizeof(mdays) / sizeof(mdays[0]); m++) {
    int sub = mdays[m] + (m == 1 && isleap(year));
    if (days < sub)
      return days;
    days -= sub;
  }
  return days;
}

/*
 * Return the 0...11 month number.
 */
static int
cdf_getmonth(int year, int days)
{
  size_t m;

  for (m = 0; m < sizeof(mdays) / sizeof(mdays[0]); m++) {
    days -= mdays[m];
    if (m == 1 && isleap(year))
      days--;
    if (days <= 0)
      return (int)m;
  }
  return (int)m;
}

int
cdf_timestamp_to_timespec(struct timeval *ts, cdf_timestamp_t t)
{
  struct tm tm;
#ifdef HAVE_STRUCT_TM_TM_ZONE
  static char UTC[] = "UTC";
#endif
  int rdays;

  /* XXX 5.14 at least introdced 100 ns intervals, this is to do */
  /* Time interval, in microseconds */
  ts->tv_usec = (t % CDF_TIME_PREC) * CDF_TIME_PREC;

  t /= CDF_TIME_PREC;
  tm.tm_sec = (int)(t % 60);
  t /= 60;

  tm.tm_min = (int)(t % 60);
  t /= 60;

  tm.tm_hour = (int)(t % 24);
  t /= 24;

  /* XXX: Approx */
  tm.tm_year = (int)(CDF_BASE_YEAR + (t / 365));

  rdays = cdf_getdays(tm.tm_year);
  t -= rdays - 1;
  tm.tm_mday = cdf_getday(tm.tm_year, (int)t);
  tm.tm_mon = cdf_getmonth(tm.tm_year, (int)t);
  tm.tm_wday = 0;
  tm.tm_yday = 0;
  tm.tm_isdst = 0;
#ifdef HAVE_STRUCT_TM_TM_GMTOFF
  tm.tm_gmtoff = 0;
#endif
#ifdef HAVE_STRUCT_TM_TM_ZONE
  tm.tm_zone = UTC;
#endif
  tm.tm_year -= 1900;
  ts->tv_sec = mktime(&tm);
  if (ts->tv_sec == -1) {
    errno = EINVAL;
    return -1;
  }
  return 0;
}

int
/*ARGSUSED*/
cdf_timespec_to_timestamp(cdf_timestamp_t *t, const struct timeval *ts)
{
#ifndef __lint__
  (void)&t;
  (void)&ts;
#endif
#ifdef notyet
  struct tm tm;
  if (gmtime_r(&ts->ts_sec, &tm) == NULL) {
    errno = EINVAL;
    return -1;
  }
  *t = (ts->ts_usec / CDF_TIME_PREC) * CDF_TIME_PREC;
  *t = tm.tm_sec;
  *t += tm.tm_min * 60;
  *t += tm.tm_hour * 60 * 60;
  *t += tm.tm_mday * 60 * 60 * 24;
#endif
  return 0;
}

char *
cdf_ctime(const time_t *sec, char *buf)
{
  char *ptr = ctime_r(sec, buf);
  if (ptr != NULL)
    return buf;
  (void)snprintf(buf, 26, "*Bad* 0x%16.16llx\n", (long long)*sec);
  return buf;
}


#ifdef TEST
int
main(int argc, char *argv[])
{
  struct timeval ts;
  char buf[25];
  static const cdf_timestamp_t tst = 0x01A5E403C2D59C00ULL;
  static const char *ref = "Sat Apr 23 01:30:00 1977";
  char *p, *q;

  cdf_timestamp_to_timespec(&ts, tst);
  p = cdf_ctime(&ts.tv_sec, buf);
  if ((q = strchr(p, '\n')) != NULL)
    *q = '\0';
  if (strcmp(ref, p) != 0)
    errx(1, "Error date %s != %s\n", ref, p);
  return 0;
}
#endif
